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AUTOGENOUS 

WELDING 

THE OXY-ACETYLENE AND OXY-HYDROGEN 
PROCESSES FOR WELDING AND 
CUTTING METALS 























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NUMBER 125 

AUTOGENOUS WELDING 

» • 

CONTENTS 

Introduction -----------3 

Oxy-acetylene and Oxy-hydrogen Process of Metal Cut¬ 
ting and Autogenous Welding.4 

Pre-heating Metals to be Welded by the Oxy-acetylene 
Process, by J. F. Springer ------ 20 

Oxy-acetylene Welding of Tanks and Retorts, by J. F. 
Springer -.26 

Autogenous Welding as a Means of Repairing Cylin¬ 
ders, by Henry Cave .34 

Manufacture of Tubing by Autogenous Welding, by J. 

F. Springer.38 

) 


> ) 

• *> > 

) 


Copyright, 1914, The Industrial Press, Publishers of ISlAt'UiNERT, 
140-148 Lafayette Street, New York City 







^ Xr 

C'CI.A369974 ' 

MAY “2 1314 

Ho / 


INTRODUCTION 


During the last fifteen years several interesting and valuable 
processes for joining metal parts have been developed. The processes 
of ordinary forge welding, soldering, and brazing are very old, hav¬ 
ing been used from time immemorial. Forge welding is applicable only 
to the joining of wrought iron, low carbon steel and a few alloys. For 
the sake of accuracy we must except gold which in the pure, annealed 
state has the curious property of welding cold under pressure; but com¬ 
mercially speaking, forge welding is limited to wrought iron and mild 
steel. Soldering can be used only on small, light work for joints 
which are exposed to ordinary temperatures and those slightly above 
the boiling point of water, inasmuch as the melting point of solder 
is about 400 degrees F. Brazing, that is, the joining of parts by the 
fusion of a spelter, is applicable to iron, steel, copper, brass, and other 
metals. On many kinds of work it is a process rather uncertain in 
results, even in the hands of experts, unless a good equipment is pro¬ 
vided for controlling the heat and manipulating the work. 

Until within a few years, cast iron could not be brazed successfully, 
because of the presence of the free carbon in the iron. The brazing 
of cast iron was made possible by the “ferrofix” process, which first 
decarbonizes the joint, placing the metal in much the same condition 
as wrought iron, so far as the action of brazing is concerned, and then 
brazing follows in the usual manner. ' Prior to this discovery the 
Thompson electric welding process had been developed, by which almost 
all commercial metals except cast iron are quickly and homogeneously 
welded together, the joint being raised to incandescence by the fiow of 
the electric current. This process has had a very successful com¬ 
mercial development, and is now used for making thousands of welds 
daily. The electric welding processes are essentially “autogenous,” an 
expression that will be explained further on. 

The thermit process developed by Goldschmidt is unique. Intense 
heat is produced by the chemical reaction of pure aluminum and iron 
oxide in a finely divided state, the temperature rising as high as 
5,400 degrees F. One product of the reaction is pure molten iron or 
mild steel so hot that when poured upon the broken ends of a forging, 
surrounded by a suitable mold, the parts are instantly melted, and the 
whole fushed together with a mass of hot metal which, as it cools, 
binds the joint together with a perfectly homogenous union. 

The latest development in the joining of metals, which is now as¬ 
suming the proportions of an important commercial development, is 
the so-called autogenous gas fiame process. The term autogenous 
welding is in some danger of becoming applied exclusively to various 
systems of gas fiame welding. The fiame produced by the combustion 


4 


NO. 125—AUTOGENOUS WELDING 


of hydrogen and oxygen, or acetylene and oxygen, is so hot that the 
parts adjacent to the metal joint are quickly melted together, forming 
a perfect union; hut the meaning of autogenous welding is simply a 
welding of its own kind, the parts being joined together without the 
introduction of spelter, solder or any foreign material. Hence any 
method of joining metals by fusion of the joint which does not require 
the introduction of foreign material to make the weld is autogenous. 
Right here it may be said that the autogenous weld is the only re¬ 
liable joining of aluminum parts that has been discovered. 

An autogenous joint, when properly made, must be as strong as the 
adjacent metal, provided no change has been made in the character- 
tics of the metal because of the heat. A broken forging that has been 
subjected to special heat treatment to improve its physical character¬ 
istics could not be autogenously welded and made as strong in the 
joint as before, without, of course, again being heat treated. The im¬ 
portance of gas flame autogenous welding in jointing thousands of 
manufactured articles, which are now brazed, riveted or bolted 
together, is obvious. 


CHAPTER I 


THE OXY"ACETYLENE AND OXY-HYDROQEN 
PROCESSES OP METAL CUTTING AND 
AUTOGENOUS WELDING 

Within the past few years a valuable tool, unique in its character¬ 
istics, has been developed for cutting, shaping, and welding metals. 
This is the oxy-acetylene “torch,” which now is so well advanced that 
it bids fair to displace other emergency cutting and welding means 
to a large extent. The oxy-acetylene process had its inception in 
France, the first experimenter being Mr. Edmund Fouche, of Paris, 
who began his work on it in 1901. The principle of the oxy-acetylene 
torch or burner is essentially the same as that of the oxy-hydrogen 
blow-pipe, which has been used for many years for generating intense 
heat. But though the oxy-hydrogen flame is intensely hot, the flame 
produced by the oxy-acetylene torch is so much hotter that the two are 
not in the same class. The temperature produced by the oxy-hydrogen 
flame is rated by authorities at about 4,000 degrees F., while that of the 
oxy-acetylene flame is estimated at about 6,300 degrees F. Not only is 
the flame of acetylene much hotter than hydrogen, but the number of 
B. T. U. per cubic foot is about five times as great, being as 330 to 
1600. Hence both the intensity and amount of heat is greatly in¬ 
creased in the flame of the oxy-acetylene torch. A comparison between 
the two instruments has been aptly put as like that of “a finely pointed 
tool and a blunt instrument.” 


5 


OXY-ACETYLENE PROCESS 

Definition of Autogenous Welding—Brief Explanation of Method 

As already mentioned in the introductory paragraphs, the process 
of fusing and uniting metals by the application of intense heat with¬ 
out compression or the use of a flux is termed “autogenous welding.” 
The temperature required is obtained by the combustion of a mixture 
of gases, such as oxygen and acetylene or oxygen and hydrogen. One 
or both of these gases may be under pressure. The gases are mixed 
in the nozzle of the torch prior to combustion. Ordinarily, the weld is 
formed by fusing in additional material between the surfaces of the 
joint. This material is in the form of a rod or wire and may or may 
not be of the same composition as the material being welded. 

Development of Oxy-acetylene Process 

The commercial development of metal-cutting and autogenous weld¬ 
ing has been taken up by several concerns in the United States and 
Europe. The processes are essentially the same, the difference being 
in the construction of the torches and tlm manner in which the gases 
are generated. Great difficulties were at first met with in cheaply pro¬ 
ducing pure oxygen gas. The cheap production of acetylene had, to a 
great extent, been satisfactorily solved in the extensive development 
of acetylene lighting, but even this art had to be further developed to 
meet all the requirements of metal welding and cutting work. There 
are four or five commercial means of making oxygen, these being 
principally the oxone or barium process, the liquid air process, the 
epurite process, and the chlorate of potash process. The latter process 
is used by the Davis-Bournonville Co., New York, and the following 
notes relate to the development of the art of metal cutting and auto¬ 
genous welding, as reached by this concern. 

A few of the purposes for which cutting and welding torches are 
commonly used are as follows: For cutting steel,wreckage, steel pil¬ 
ing, steel beams in structural work, risers from,steel castings, openings 
through steel plates, etc.; for welding seams, reclaiming cracked cast¬ 
ings, filling blowholes in castings, adding metal to worn surfaces to 
secure the original thickness, welding piping without removal, filling 
holes that have been incorrectly located, replacing broken gear teeth 
by welding in new material, sealing riveted seams to secure tight 
joints without calking, etc. 

Generating- the Oxygen and Acetylene 

The chlorate o-f potash process of generating oxygen is well known, 
being perhaps the simplest method. It will be found described in 
elementary works on chemistry. The oxygen of chlorate of potash can 
be driven off by gentle heat, and, in practice, the potash is placed in a 
closed retort and subjected to a comparatively low temperature. The 
reduction is facilitated by the addition of black dioxide of manganese 
in the proportion of 14 pounds of manganese to 100 pounds potash. 
The oxygen gas is passed through scrubbers and is pumped into re¬ 
ceivers. The pressure in the receivers is varied according to the use. 


6 


NO. 125—AUTOGENOUS WELDING 


it being desirable to compress from 125 to 150 pounds per square incli 
for metal cutting, while 15 pounds pressure suffices for autogenous 
welding. The acetylene gas is produced in the Davis generator which 
is adapted to all pressures up to 15 pounds per square inch. The 
machine is automatic and feeds lump carbide perfectly up to sizes 
that pass through 1-inch screen. The theoretical quantity of water to 
carbide is about V 2 pound to 1 pound carbide, but to absorb the heat 
of the chemical transformation the generator is required to have a 
water capacity of 1 gallon water to 1 pound carbide. For repair shops 
and work outside of the shop, a portable apparatus is required, and for 
such purposes the oxygen and acetylene gases are stored in small 
cylinders. The storage of oxygen is a simple matter of pumping the 
gas into the cylinders until the required pressure lias been reached. 
The storage of undiluted acetylene under pressure in tanks is im¬ 
practicable, but fortunately, it was discovered in 1896 by Claude and 
Hesse, two French engineers, that acetone, a fluid derived from the dry 
distillation of wood, is a remarkable solvent for acetylene, being cap¬ 
able of absorbing 25 times its volume at 60 degrees F. for each atmo¬ 
sphere. At ten atmospheres, or 150 pounds pressure per square inch, 
a gallon of acetone absorbs 250 gallons of acetylene gas. When ab¬ 
sorbed by acetone, acetylene is non-explosive under heavy pressure. 
A red-hot wire might be thrust into the receiver with absolutely no 
effect, provided there is no free space occupied by acetylene gas. 
To prevent the possibility of there being free spaces for the accumula¬ 
tion of gas, acetylene storage tanks were designed by Mr. Edmund 
Fouche, which are packed with porous brick, asbestos or other neutral 
porous material, thus Ailing the entire free spaces and affording stor¬ 
age for the acetone and acetylene gas only in the cells of the Ailing. 

Impurity of Oxygen 

♦ 

It is of considerable importance to understand the effect of impure 
oxygen. The impurities which have any especial claim to attention are 
those which arise through the presence of nitrogen or hydrogen. If 
the oxygen is prepared by the liquefaction of air, some percentage of 
nitrogen will be very sure to be present. Nitrogen itself seems to be 
harmless, in so far as any ill effect on the metal is concerned. It is, 
however, practically unburnable, and so clogs the action of the oxygen. 
It probably also tends to cool the heating flame and thus retard the 
work. In the manufacture of oxygen by the electrolytic process, the 
principal impurity will probably be hydrogen. As hydrogen is a gas 
that is readily combustible it has but little effect on the heating flame, 
but in the cutting stream of oxygen its presence doubtless gives rise 
to a clogging effect similar to that of nitrogen. At all events, whether 
we account for the result in one way or another, the presence of nitro¬ 
gen or other impurities in the oxygen supply has the effect of retarding 
the cutting operation. This retardation means a labor loss in addition 
to a gas loss, besides hindering output. Certain experiments carried 
out abroad will assist us in seeing just how serious the retardation is. 


OXY-HYDROGEN PROCESS 


7 


Table 1 gives the results of twenty-six experiments, all tried on sheets 
of the same kind, of the same thickness, and with the same style of 
torch. 

It will be seen at once that the purity of the oxygen plays a most 
important part in the efficiency with which cutting may be accom¬ 
plished. With oxygen 85.5 per cent pure, it requires three times as 

TABLE I. TIME REQUIRED FOR OXY-HYDROGEN CUTTING OF METALS 

Siemens-Martin sheet steel, 1.18 inch thick. Oxy-hydrogen procedure. Gas 
consumption per minute: Hydrogen. 1.06 cubic foot; oxygen, 0.28 cubic foot. 
Oxygen pressure = 1.5 atmosphere = 22 pounds per square inch. 


Purity of 
Oxygen, 
expressed as 
Percentage 

Length of 
Cut, 

in Inches 

Time required 
in Making 
Cut, 

in Seconds 

Time required 
to Cut 

One Foot, 
in Minutes 

Average Time 
required to 
Cut One Foot, 
in Minutes 

99.00 

28.0 

182 

1.30 


99.00 

21.3 

140 

1.31 


99.00 

18.9 

120' 

1.27 

1.30 

99.00 

34.3 

228 

1.33 


99.00 

29.9 

196 

1.31 


98.50 

31.5 

210 

1.33 


98.50 

41.7 

330 

1.58 


98.50 

41.7 

320 

1.53 

1.52 

98.50 

39.4 

310 

1.53 

98.50 

27.6 

225 

1.63 


98.50 

18.9 

150 

1.53 


95.50 

44.5 

426 

1.91 

1.91 

95.50 

32.3 

295 

1.91 

94.75 

25.2 

270 

2.14 


94.75 

21.7 

240 

2 21 


94.75 

33.9 

364 

2.15 

2.21 

94.75 

23.6 

270 

2.29 


94.75 

41.6 

475 

2.28 


90.50 

34.3 

480 

2.80 


90.50 

36.6 

500 

2.73 


90.50 

32.7 

480 

2.94 

2.88 

90.50 

35.4 

495 

2.80 


90.50 

29.9 

470 

3.14 


85.50 

43.3 

870 

4.02 


85.50 

21.7 

420 

3.87 

3.99 

85.50 

23.6 

480 

4.07 

Machinery 


long to cut the 1.18-inch plate as with oxygen 99 per cent pure. This 
means that the cost is three times as much. Exen the one-half of one 
per cent drop from the 99.0 per cent oxygen to the 98.5 per cent quality 
means an increase in the expense amounting to 16 per cent. So even 
if the better grade of oxygen slicmld cost more, we see from the fore¬ 
going that it would have to cost a great deal more to make it a matter 
of no importance which grade of oxygen is used. 







































8 


NO. 125—AUTOGENOUS WELDING 


In Table II the same kind of steel and the same thickness of sheets 
are to be understood as in Table I. The pressure of the oxygen is in¬ 
creased, however. Note especially that here we have the alternative 
procedure with acetylene gas. 

It will be noted that we do not have any experiments here with 99 
per cent oxygen. Comparing the 98.5 per cent purities in Tables I and 
II, we see that the acetylene cutting has the advantage. The result 
with 94.75 per cent oxygen, hydrogen cutting, when compared with 


TABLE II. TIME REQUIRED FOR OXY-ACETYLENB CUTTING OP METALS 

Siemens-Martin sheet steel, 1.18 inch thick. Oxy-acetylene procedure. Acety¬ 
lene consumption per minute: 0.153 cubic foot. Oxygen pressure: 2 atmos¬ 
pheres = 29.4 pounds per square inch. 


Purity of 
Oxygen, 
expressed as 
Percentage 

Length of 
Cut 

in Inches 

Time required 
in Making 
Cut, 

in Seconds 

Time required 
to Cut 

One Foot, 
in Minutes 

Average Time 
required to 
Cut One Foot, 
in Minutes 

98.50 

17.3 

123 

1.42 


98.50 

28.3 

192 

1.36 


98.50 

32.3 

228 

1.41 

1.40 

98.50 

33.9 

230 

1.36 

98.50 

28.3 

200 

1.41 


98.50 

28.3 

202 

1 43 


96.50 

33.9 

255 

1.50 


96.50 

45.3 

860 

1.59 


96.50 

47.2 

380 

1.61 


96.50 

37.8 

320 

1.69 


96.50 

58.3 

480 

1.65 

1.63 

96.50 

44.1 

370 

1.68 


96.50 

41.7 

340 

1.63 


96.50 

30.7 

245 

1.60 


96.50 

44.9 

380 

1.69 


94.50 

34.6 

400 

2.31 


94.50 

43.3 

510 

2.36 

2.83 

94.50 

43.3 

520 

2.40 

94.50 

35.4 

400 

2.26 

Machinery 


the work done with 94.50 per cent, acetylene cutting, indicates that the 
efficiencies at this degree of impurity are about the same. This would 
become all the clearer by drawing curves illustrative of the last 
columns in Tables I and II and then superimposing them on each 
other. It must be borne in mind, however, that the oxygen pressure 
is distinctly higher with the acetylene experiments. 


The Oxy-acetylene Torch 

Fig. 1 shows the Davis-Bournonville Co.’s cutting and welding torchesT 
The upper illustration is the cutting torch and differs from the weld¬ 
ing torch shown in the lower illustration simply in that it has an 
auxiliary detachable oxygen tube secured to the side. The welding 
torch has an acetylene gas tube and an oxygen tube which combine 



























WELDING TORCHES 


9 


in a tip or nozzle from which the united gases flow and burn. The 
upper tube in each illustration is for oxygen, while the lower tube is 
for acetylene, the two gases uniting at the end of the removable tip 
within the body of the torch. 

In Fig. 2 is shown a line engraving of a standard oxy-acetylene 
torch for medium and heavy welding. As will be seen, there are two 
small pipes which have hose connections at one end. The opposite 
ends are attached to a head which holds the torch tip or nozzle. The 
pipe for acetylene opens into a cylinder which serves as a handle and 
is packed with a porous material that makes it impossible for the 
flame to pass this point. However, “flash back” is not likely to extend 
back of the tip. The tips are interchangeable, different sizes being 



Fig. 1. Davis-Bournonville Oxy-acetylene Cutting and Welding Torch 


required for various classes of work. The mixture of the oxygen and 
acetylene gases takes place within the tip. The acetylene is admitted 
under lower pressure than the oxygene, and through inlets at right 
angles to the oxygen inlet to insure thorough mixing. Regulators on 
the storage tanks serve to control the working pressures of both gases. 

Adjusting the Torch 

Before lighting the torch, the regulator on the oxygen tank should 
be set to give the required pressure. The average pressures used for 
welding different thicknesses of metal are given in Table III. The 
acetylene is lighted first, the regulator being adjusted so that there is 
a fairly strong flame. The full pressure of the oxygen is then turned 
on, after which the acetylene pressure is varied by means of the 
regulator until the two cones which appear in the flame at first are 
merged into one smaller cone. After this cone is formed, no more 
oxygen should be added. It is also well to occasionally test the cone 
by increasing the acetylene pressure slightly, which will immediately 
< 3 ause an extension at the point of the cone. When the cone is 


















10 


NO. 125—AUTOGENOUS WELDING 


properly formed, it will be neutral, so that it will neither oxidize 
(burn) or carbonize the metal. An excess of oxygen will cause burn¬ 
ing and oxidation, whereas an excess of acetylene will carbonize the 
metal. The tip of the cone should just touch the metal being welded, 
but not the point of the torch, as this might cause a “flash back.” An 
excessive discharge of sparks indicates that too much oxygen is being 
used and that the metal is being burned or oxidized, although when 
welding thick metals, there will be a considerable volume of sparks, 
even though the flame is neutral. 

Size of Torch Tip 

The proper size of tip to use for welding depends upon the thickness 
of the work and the rate at which the heat is dissipated. Sometimes 
the rate of conduction and radiation is affected by the location of the 
parts to be welded. In general, heavy parts will conduct the heat more 
rapidly from the working point, and to offset this loss of heat a larger 



Fig, 2. Oxy-acetylene Torch for Medium and Heavy Welding 


tip is used. In any case, the tip should be as small as is compatible 
with good work, to economize in the use of gases. If the flame is too 
small for the thickness of metal being welded, the heat will be radiated 
almost as fast as produced; hence, the flame will have to be held so 
long at one point to effect a weld that the metal will be burned. On 
the other hand, if the flame is too large, the radiation may be insuf- 
flcient to prevent burning the molten metal. The tip should give a 
flame that will reduce the metal to a plastic, molten condition (not too 
fluid), covering a width approximately equal to the thickness of the 
metal being welded. 

High- and Low-pressure Torches 

The difference between high- and low-pressure oxy-acetylene welding 
and cutting torches, according to the generally accepted meaning of 
these terms, is in the pressure of the acetylene gas. The oxygen, in 
each case, is under ^ pressure of one or two atmospheres. With a high- 
pressure torch, the acetylene gas has a working pressure of one pound 
or more (depending upon the nature of the work); in the low-pressure 
type, the acetylene gas only has a pressure of a few ounces. The 
operation of the low-pressure torch is on the principle of an injector, 
in that the jet of oxygen draws the acetylene into the mixing chamber 
which is in the torch tip. The proportion of oxygen to acetylene varies 
somewhat with different torches; it usually ranges between 1.14 to 1 
and 1.7 to 1, more oxygen being consumed than acetylene. 














MAKING A WELD 


11 


Making Autogenous Welds 

To become proficient in the art of autogenous welding requires ex¬ 
perience and practice, but a knowledge of some of the fundamental 
principles will enable the operator to make more rapid progress. It 
is advisable to begin by welding thin strips of iron or steel not over 
% inch in thickness. Such light metals can be welded without the 
addition of a filling-in material. The torch should be given a rotary 
motion accompanied by a slight upward and forward movement with 
each rotation. This movement tends to blend the metal and reduces 
the liability of overheating. If comparatively thick materials are to 
be welded, the edges should be beveled (by chipping, or in any other 
convenient way), as shown in Fig. 3. The beveled surfaces are then 
heated by a circular movement of the flame, care being taken to melt 
them to a soft, plastic state without burning the metal. Wherever 
fusion occurs, new metal should be added from a “welding rod,” the 
composition of which is suitable for the work in hand. In continuing 



the heating operation, the flame should be swung around in rather 
small circles and be advanced slowly to distribute the heat and pre¬ 
vent burning. The surface should be thoroughly fused before adding 
metal from the welding stick, and the latter should be held close to, 
or in contact with, the surface. The heat is then radiated from the 
welding rod to the work, whereas if the metal were allowed to drop 
through the flarne, it might be burned to an injurious extent. When 
the weld is completed, it is advisable to pass the torch over it, so that 
all parts will cool from a nearly uniform temperature. 

When welding two parts together, it is important not to heat one 
more than the other, because the hottest piece will expand most and 
the weld may crack in cooling as the result of uneven contraction. 
When making heavy welds, the parts should be brought to a red heat 
for a distance of about three times the thickness on each side of the 
weld, for thicknesses up to one inch, the distance being increased some¬ 
what for heavier parts. The following suggestions are given by the 
Davis-Bournonville Co., and apply to the welding of various metals. 

Welding- Cast Iron 

If the work is in such a form that it may crack in cooling, it should 
be pre-heated, but not enough to warp the metal, no part being 
heated to a dark red except at the welding point. (See Chapter II.) 
Whether the metal is pre-heated or not, it should be covered as soon as 







12 


NO. 125—AUTOGENOUS WELDING 


the weld is finished and be allowed to cool slowly. If the metal is 
more than i/4 inch thick, the edges should be beveled at an angle of 
about 45 degrees on each side. For comparatively heavy welds, it is 
well to leave three small points of contact for aligning the broken parts 
in the original position. To make the weld, the flame should be passed 
for some distance around the fracture and then be directed onto it until 
the metal is cherry-red. When this occurs, have an assistant throw 
on a little scaling powder, and when the metal begins to run, add cast 
iron from the cast-iron “welding stick,” which should be of specially 
refined material. Powder should only be added when the metal does 
not flow well, as little as possible being used. Never attempt to re- 


TABLE III. APPROXIMATE HOUR COST OF OXY-ACETYLENE WELDING 

(Davii^-Bouruonville Co.) 

Oxygen at 3 cents per cubic foot, acetylene at 1 cent per cubic foot 


Tip No. 

Thickness 
of Metal, 
Inches 

Acetylene 

Pressure, 

Pounds 

Oxygen 

Pressure. 

Pounds 

Cubic Feet 
per Hour 

Lineal Feet 
Welded 
per Hour 

Cost of 
Gases 

j Cost of 

Labor 

Total 

Hour 

Cost 

Cost per 

Lineal 

Foot 

Acety¬ 

lene 

Oxy¬ 

gen 

1 


1 

2 

3.21 

3.65 

30 

$0,142 


$0,442 

$0,015 

2 

A 

2 

4 

4.84 

5.50 

25 

0.213 


0.513 

0.020 

3 

3^ 

3 

6 

8.14 

9.28 

20 

0.360 

53 

o 

0.660 

0.033 

4 

i 

4 

8 

12.50 

14.27 

15 

0.553 

A 

0.853 

0.057 

5 


5 

10 

17.81 

21.32 

9 

0.818 

0) 

ft 

1.118 

0.124 

6 

i 

6 

12 

24.97 

28.46 

6 

1.103 


1.403 

0.234 

7 


6 

14 

33.24 

37.90 

5 

1.469 

C 

0) 

1.769 

0.354 

8 

1 

6 

16 

41.99 

47.87 

4 

1.856 

o 

o 

2.156 

0.539 

9 

i 

6 

18 

57.85 

65.95 

3 

2.557 

CO 

2.857 

0.952 

10 

1 

6 

20 

82.50 

94.05 

2 

3.646 


3.946 

1.973 


weld pieces that have been previously welded or brazed, without first 
cutting away all of the old metal. 


Welding- Steel 

Steel less than % inch thick can be welded without the addition 
of any wielding metal. If the thickness exceeds % inch, the edges 
should be beveled or chamfered. It is very important not to add the 
welding material until the edges are fused or molten at the place 
where the weld is being made. The welding metals should be of 
special wire, and in no case should the flame be held at one point 
until a foam is produced, as this is an indication that the metal is 
being burned. Do not hold the flame steadily in the center of the 
weld, but give it a circular motion with an uplifting movement at 
each revolution, the object being to drive the molten metal toward the 
center of the w^eld. When welding a crack located in the middle 
of a heavy steel sheet, begin by chamfering the metal on each side 
of the fracture at an angle of 45 degrees, the slope extending to the 
bottom; then apply the welding torch to the sheet beyond the end 
of the crack, until there is sufficient expansion to open the crack 






























WELDING ALUMINUM 


13 


perceptibly. The weld should then be made, and, as a rule, it will 
be found that the expansion will compensate for the contraction when 
cooling. A slight excess of oxygen is less harmful than an excess 
of acetylene, but it is important to so adjust the gases that the flame 
is neutral. When the weld is completed, pass the torch over it and 
the surrounding metal, as previously mentioned. 

Welding- Aluminum 

Aluminum that is to be welded should be scraped and cleaned, and 
if the stock is more than % inch thick, it is advisable to chamfer the 
edges. The oxy-acetylene flame can be reduced or “softened” by 
using an excess of acetylene to a degree which will be indicated by 
the extension of the acetylene cone from 1 to iy 2 inch beyond the 
white cone. This excess of acetylene does not injure aluminum, but 
lowers the flame temperature which is desirable when welding alumi¬ 
num. Before welding this metal, heat the entire piece in a charcoal 
Are or furnace to about 300 or 400 degrees below the melting point. 
Then cover it with asbestos or other material (leaving an opening 
where the weld is to be made), in order to keep the work hot until 
the weld is completed. When the weld is made it should be covered 
completely, as a protection against drafts, to insure slow cooling and 
prevent shrinkage cracks. Many aluminum parts can be welded with¬ 
out pre-heating, such as lugs or projecting pieces broken off com¬ 
pletely. When a welding flame is applied to aluminum, it will be 
noticed that the metal does not run together. A flattened iron rod 
should be used to puddle the aluminum, and this rod should be wiped 
frequently, so that it will not become coated. The rod should not be 
allowed to reach a red heat, thus causing oxide of iron to form on 
it, as this would cause a defective weld. A good aluminum flux will 
be found advantageous. The aluminum to be added should be in 
sticks of special composition, obtainable from the makers of welding 
apparatus. The quality of the welding metal has much to do with the 
quality of the weld. 

Welding Brass and Copper 

For brass, adjust the flame until there is a single cone, as for steel 
welding. Keep the point of the white flame slightly away from the 
weld, according to the thickness of the piece, so that the heat will 
not be sufficient to burn the copper in the brass or volatilize the zinc. 
If a white smoke appears, remove the flame, as this indicates excessive 
heat. A little borax should be used as a flux. For brass welding, it 
is advisable to use a tip about one size larger than for the same 
thickness of steel. As the weld is really cast brass, it will not have 
the strength of rolled sheet brass. Do not breathe the fumes while 
welding brass. 

To weld copper use the same kind of flame as for steel, but a much 
larger tip for corresponding dimensions, because of the great radiat¬ 
ing property of copper. Pre-heating is neessary when a large piece 
of copper is to be welded, as otherwise so much heat from the torch 


14 


NO. 125—AUTOGENOUS WELDING 


will be dissipated by radiation that little will be left for fusing the 
metal. Copper will weld at about 1930 degrees F.; hence, the flame 
need not have so high a temperature as for steel and it must not be 
concentrated on so small a surface. On account of the radiation, 
however, the total quantity of heat must be greater. Welded copper 
has the strength of cast copper, but can be rendered more tenacious 
by hammering. The radiation of heat from copper can be consider¬ 
ably lessened by covering it with asbestos sheets while heating. To 
weld copper to steel, first raise the steel to a white heat (the welding 



Fig:, 4. Welding together the Parts of a Drawn Steel Retort. The 
Operator feeds the Joint with a Special Grade of Iron Wire 


point); then put the copper into contact with it and the two metals 
wall fuse together. When the copper begins to flow, withdraw the 
flame slightly to prevent burning. 

Welding- Miscellaneous Metals 

To weld high-speed steel to ordinary machine steel, first heavily 
coat the end of the high-speed steel with soft special iron, obtain¬ 
able from the makers of welding outfits. This can be done without 
heating the high-speed steel to the burning point. After cooling, the 
high-speed steel can be welded to ordinary machine steel without 
burning, but experience is required to make a good weld of this kind. 

To weld cast iron to steel, cast-iron rods are used as welding ma¬ 
terial. The steel must be first heated to the melting point, as cast 
iron melts at a lower temperature. A very little scaling powder 
should be used. 





WELDING OPERATIONS 


15 


The welding of malleable iron is difficult for several reasons. If 
malleable iron is raised to the melting point and kept there for any 
length of time, the metal becomes spongy and changes to what is 
practically cast iron. To weld it, coat the edges with soft special 
iron, using a little scaling powder, and then finish the weld by the 
addition of special iron. To fill blowholes in malleable iron, use cast 
iron for a filler, and to avoid hard spots, pre-heat the metal so that 
the oxy-acetylene fiame is used as little as possible. 

Certain grades of cast steel can be welded more easily than ordinary 
rolled steel, but other grades, especially of high-carbon composition, 
are very difficult to weld and some cannot be welded at all. When 
difficulty is experienced, the addition of one or two drops of copper, 
melted into the weld, will cause the metal to flow and a fairly good 
weld can be made, but copper is likely to harden the metal so that 
it cannot be machined except by grinding. 

Filling- Blowholes 

To fill large blowholes in brass or copper castings, pre-heat the 
casting to a temperature between 200 and 400 degrees F. below the 
melting point, or to a bright red color. Have some of the same metal 
melted in a crucible ready to pour; then apply the torch to the blow¬ 
hole to be filled and when the walls of the hole have been brought 
to the melting point, gradually pour in the metal, keeping the walls 
fused by using the flame. Continue mixing the poured metal with 
the molten metal of the walls, until the blowhole is filled. 

Spots in Welding 

When making heavy welds, there often is a spot in the middle 
of a weld where the metal refuses to flow, because the metal is not 
hot enough surrounding this spot, the heat being absorbed by the 
cold metal; consequently, the added metal is chilled. To remedy this, 
play the flame in a radius of from % to 1 inch, around the refractory 
point until the surrounding metal is at a white heat; then apply the 
flame to the spot itself and it will quickly unite with the other molten 
metal. 

Examples of Welding Operations 

Fig. 4 illustrates the welding of thin steel retorts for generating 
oxygen gas. The material for the retorts is bought in drawn shape, 
one part being made with a collar and the other having a rounded 
bottom. The length of the retort is too great to permit its being 
drawn in one piece, hence the necessity of welding the two parts 
together near the center. The following is the approximate cost of 
welding 1/16-inch metal. The consumption of acetylene is 2.8 cubic 
feet per hour; of oxygen 3.6 cubic feet at a pressure of 8 to 10 pounds. 
The rate of welding is about 50 feet per hour, and with labor at 30 
cents per hour, the total cost per hour is 43.6 cents, or less than 9/10 
per cent per lineal foot. The cost of welding increases with the thick- 


16 


NO. 125—AUTOGENOUS WELDING 



ness of material, of course, reaching an estimated cost of 80 to 95 cents 
per lineal foot for 7/16- to Va-inch thick metal. 

In Fig. 5 is illustrated the welding of a broken flange on a casting. 
This job, which would have been difficult and expensive by brazing, 
was easily accomplished. In this illustration, as in Fig. 4, the operator 
is shown feeding material into the weld, the same as a tinner feeds 
solder when soldering. For welding steel and wrought iron a special 
iron wire is used as already mentioned, and for welding cast iron, 
rods of cast iron. 

Pre-heating- 

Parts to be welded together autogenously are often pre-heated by the 
use of a blow-torch, gas furnace, charcoal Are, etc. This pre-heating 


Fig-. 5. Welding the Broken Flange of a Cast-iron Base. The 
Operator feeds the Joint with a Cast-iron Rod 

is done either to economize in gas consumption or to expand the metal 
before welding, in order to compensate for contraction in cooling. 
Usually it is advisable to pre-heat comparatively heavy, thick metals 
(especially if cast) before welding. This equalizes the internal strains, 
and very materially reduces the cost. In many instances, it is much 
better to produce expansion before welding, than to attempt to care 
for the contraction afterward. When there is a straight crack, it can 
usually be opened uniformly by heating the metal at each end and 
keeping it hot while the weld is being made. As a rule, the expansion 
obtained by heating at the ends will compensate for the contraction 
which accompanies cooling. When a part has been pre-heated, it is 
well to place sheets of asbestos over it to protect the operator and 
prevent heat radiation, the surface to be welded being exposed. Where 







METAL CUTTING 


17 


a piece of metal has been severed completely or a projection has been 
broken off, pre-heating will not be necessary. This subject will be 
dealt with in detail in a following chapter. 

Cutting- Metals with Oxidizing Flame 

The oxy-hydrogen and oxy-acetylene flames are especially adapted to 
cutting metals. When iron or steel is heated to a high temperature, 
it has a great affinity for oxygen and readily combines with it to form 
different oxides which causes the metal to be disintegrated and burned 
with great rapidity. The metal-cutting torch operates on this principle. 
Ordinarily, two jets or flames are used: First there is an ordinary 
welding flame for heating the metal, and this is followed by a jet of 
pure oxygen, which oxidizes or burns the metal. The kerf or path left 
by the flame is suggestive of a saw cut. On some torches the oxygen 
jet is obtained by the application of a separate cutting attachment to 
a regular welding torch. This attachment is little more than a pipe 
containing a tip, which supplies a pure oxygen jet located close to the 
regular heating flame. Torches are also designed especially for 
cutting. 

Operation of Cutting Torch 

When starting a cut, the steel is first heated by the welding flame; 
then the jet of pure oxygen is turned on. The flame should be 
directed a little inward, so that the under part of the cut is somewhat 
in advance of the upper surface of the metal. This permits the oxide 
of iron produced by the jet to readily fall out of the way. If the 
flame were inclined in the opposite direction or in such a way that 
the cut at the top were in advance, the oxide of iron would accumulate 
in the lower part of the kerf and prevent the oxygen from attacking 
the metal. The torch should be held steadily and with the cone of the 
heating flame just touching the metal. When accurate cutting is 
necessary, some method of mechanically guiding the torch should be 
employed. 

Thickness of Metal to be Cut 

The maximum thickness of metal that can be cut by these high- 
temperature flames depends largely upon the gases used and the 
pressure of the oxygen; the thicker the material the higher the pressure 
required. When using the oxy-acetylene flame, it might be practicable 
to cut iron or steel up to 7 or 8 inches in thickness, whereas with the 
oxy-hydrogen flame the thickness could probably be increased to 20 or 
24 inches. The oxy-hydrogen flame will cut thicker material princi¬ 
pally because it is longer than the oxy-acetylene flame and can pene¬ 
trate to the full depth of the cut, thus keeping all the metal in a molten 
condition so that it can easily be acted upon by the oxygen cutting jet. 
A mechanically-guided torch will cut thick material more satisfactorily 
than a hand-guided torch, because the flame is directed straight into 
the cut and does not wabble, as it tends to do when the torch is held 
by hand. With any flame, the cut is less accurate and the kerf wider, 


18 


NO. 125—AUTOGENOUS WELDING 


as the thickness of the metal increases. When cutting light material, 
the kerf might not be over 1/16 inch wide, whereas, for heavy stock 
it might be ^/i or % inch wide. 

Cutting- Metal under Water 

A German engineer has designed a burner which makes it possible 
to use the hydrogen-oxygen flame for cutting metals under water. 
The burner consists of a bell-shaped head which is screwed onto an 
ordinary burner and which allows the flame to continue to burn below 



Fig. 6. Cutting Off Steel Sheet Piling with Oxygen Cutting Torch 
showing Portable Apparatus 


the water in a supply of compressed air. This process has been so 
improved of late that the cutting of metals under water is claimed 
to be effected almost as quickly as above the surface. At tests made 
with the new apparatus at the harbor at Kiel, before prominent en¬ 
gineers and representatives of the German government, a diver went 
down into the sea to a depth of about 16 feet, and, after boring a hole 
into an iron bar 2% inches square, cut off the bar in about thirty 
seconds. An iron sheet % inch thick was drilled through and cut for 
a distance of one foot in ninety seconds. 

Example of Metal Cutting- 

Fig. 6 illustrates the use of the cutting torch cutting off steel sheet 
piling. This work is done with rapidity, and is a very spectacular per- 








METAL CUTTING 


19 


formance. In the case of cutting, the combustion of the steel materi¬ 
ally raises the temperature and assists in the work. This was pointed 
out by Chevalier C. de Schwarz in a paper read before the May, 1906, 
meeting of the Iron and Steel Institute, and it gives one a startling 
idea of the power of the oxygen cutting flame when the concentration 
of the heat units produced is known. Burning 1 pound of acetylene 
with oxygen produces from 18,250 to 21,500 B.T.U. The mean value 
may be taken as about 19,750 B.T.U. per pound, and the number of 
cubic feet at atmospheric pressure at about 1414- Now% the burning of 
1 pound of steel with oxygen produces approximately 2,970 B.T.U., but 
at atmospheric pressure 1 pound of acetylene gas Alls 6,750 times the 
space of 1 pound of steel. Hence, the intensity of the heat with per¬ 
fect combustion of the steel in oxygen will be, theoretically, 

6750 X 2970 

-= 1,015 times the intensity of heat of the oxy-acetylene 

19,750 

flame. As a matter of fact, of course, this enormous temperature is 
not even remotely approached, because the metal dissolves at a far 
lower temperature and passes off in sparks, which are speedily cooled 
by the atmosphere. 

Cost of Cutting- Metals with the Oxy-acetylene and 
Oxy-hydrogen Flame 

The following flgures will give an idea of the cost of cutting metals 
by the processes described. Assuming oxygen at 3 cents per cubic foot 
and acetylene at 1 cent per cubic foot, 2 feet of 14 -inch thick steel can 
be cut per minute at a cost of 1.3 cent per foot, and 1 foot of li^-inch 
thick steel can be cut per minute at a cost of 7.6 cents per foot. This 
cost is for gas alone; the cost of labor must, of course, be added. The 
figures given are for machine-guided torches. When cutting with a 
hand-guided torch, the gas consumption will be approximately one- 
third more and the number of feet cut per hour, one-third less, than 
when the torch is mechanically guided by a special cutting machine. 
The variation, of course, depends to some extent upon the skill of the 
operator. 

When cutting with the oxy-hydrogen flame and assuming the cost 
of oxygen at 3 cents per cubic foot and the cost of hydrogen at 1% 
cent per cubic foot, the cost of the gas per foot for cutting i^-inch 
thick steel is about 7 cents and the cost of cutting 1%-inch thick steel, 
about 18 cents per lineal foot. Cutting with a hand torch increases the 
cost slightly. While the oxy-hydrogen process is thus more expensive 
than the oxy-acetylene process for thin stock, it has the advantage 
that it can be used on much heavier material than the oxy-acetylene 
flame, as explained in a previous paragraph. 



CHAPTER II 


PRE-HEATING METALS TO BE WELDED BY 
THE OXY-ACETYLENE PROCESS 

The use of the oxy-acetylene torch for heating the work from the 
ordinary open-air or room temperature to that of, say, red heat, is a 
rather wasteful method. It is frequently more economical to do this 
pre-heating by some cheaper method and then to complete the heating 
with the torch. Various methods are used for pre-heating; as a rule 
these methods are comparatively simple. A number of examples will 
be described in the following. 

In pre-heating a large cast-iron kettle, a charcoal tire was employed. 
The kettle weighed about 18,000 pounds and the metal around the 
crack, which was about two feet long, was several inches thick. The 
crack Avas in the bottom and so the kettle was overturned in order to 
make the crack more easily accessible. The pre-heating was then done 
from within the kettle, and, in this case, was not only economical but 
probably essential, as it would have been difficult to obtain the re¬ 
quired amount of heat by the torch flame alone. Asbestos sheeting Avas 
employed to protect the operator from the heat radiation. 

Repairing a Locomotive Cylinder 

In repairing a break in a locomotive cylinder. Fig. 1, the pre-heating 
Avas also done with charcoal, a temporary oven having been built up 
of loosely laid bricks, as shown in Fig. 2. The Are was kept going for 
two and one-half hours, at which time a dull red heat was secured. 
This condition was maintained for six hours longer during the weld¬ 
ing operation. It is often possible to use an ordinary blacksmith’s 
forge for the pre-heating, and if a great many similar parts are to be 
handled, a special forge and belloAvs may be found of advantage. In 
addition to the use of charcoal, torches using illuminating, producer, 
or natural gas, oil, or gasoline, may be employed; in fact, any method 
for obtaining a large amount of heat, but not necessarily a high tem¬ 
perature, can be employed. In one case, in welding a break in a loco¬ 
motive engine frame, a gasoline torch was employed for the pre-heating, 
the torch being applied throughout the welding operation. In cases 
of repetition work, special arrangements of pipes and burners may be 
advisable. 

Various Methods of Pre-heatingr 

In one plant in Europe, Avhere tubing is manufactured Avith the aid 
of power-driven* gas-welding machines, provision is made for the rolled 
•but unAvelded tube to pass through a muffle just before reaching the 
torch, so that the tube is bright red when passing under the torch. 
Sometimes the outer flame of the torch itself may be used for pre- 


PRE-HEATING 


21 



machine in welding a straight seam on the containing cans place where it is reached by the working flame. It^ is 

of their batteries. The torch, the work, and the clamping possible that this arrangement was not provided with a view 

devices are so arranged that the outer flame of the oxy- to pre-heating, but that is the effect, and a consequent econ- 

acetylene jet is divided into two long streamers. One of omy in gas consumption is the result. 




















‘>2 


NO. 125—AUTOGENOUS WELDING 


The use of the outer flame for pre-heating may come to be an impor¬ 
tant factor. A large quantity of heat is generated by this flame. In the 
machine referred to, the clamps arranged along the sides of the seam 
are beveled to afford access to the torch, the bevels being quite steep— 
about 60 degrees. The writer would suggest that similar clamping 
bars be formed in connection with regular hand-welding work, so as 
to provide a canyon-like working groove. In hand-welding larger 
sizes of tubing, it would also be practicable to provide a series of gas 
jets on a single supply pipe beneath the joint. In this way the edges 
could be pre-heated with cheap gas. 

Pre-heating- to Prevent Unequal Expansion or Contraction 

Pre-heating is often resorted to for reasons other than those of 
economy of gas consumption. It is used where the effects of ex¬ 
pansion and contraction are objectionable. The rise of 2000 degrees 
in the temperature of a metallic body occasions considerable expansion 
in every direction. For example, a 12-inch steel bar will lengthen 
about 5/32 inch. It is easily seen that the sudden swelling and re¬ 
sultant shrinking of only a small part of the work may, at times, have 
disastrous results. Take as an example the spoke of a fly-wheel with 
a piece broken out. This piece just fits into its place. If we repair this 
by making the required grooves and then filling them with new metal, 
thus producing an apparently good weld, we will find that, upon cool¬ 
ing, a break will frequently occur in the weld or at some other point, 
due to the contraction. A similar case is met with in a crack in a cast¬ 
ing. It is chipped out in order to obtain beveled edges for the flame, 
the faces are heated, and new molten material filled in. When the 
weld cools off, however, the new material is likely to shrink away from 
the walls of the crack. 

Now what can be done to meet this condition? If we could uni¬ 
formly heat the whole piece inside and outside, we should probably 
have an ideal solution, but one of the great objects in oxy-acetylene 
welding is to localize the heating. We can, however, pre-heat a larger 
portion of the whole body than is required for the welding alone, and 
in this way distribute the stresses. In the case of the flywheel, the 
broken spoke, the adjacent spokes, and the Intervening rim may be 
heated to a red heat, gradually diminishing toward the other parts of 
the wheel, so that the pre-heating itself does not introduce new stresses. 
When the new material for making the joints is filled in, the spoke is 
naturally longer than it will be at ordinary temperatures, and while 
there is a local contraction of the weld, there is also a general con¬ 
traction of the whole spoke and those adjacent, which diminishes the 
effect. In the case of a cracked cylinder casting, the pre-heating of the 
metal beyond each end of the crack, if properly done, will ordinarily 
open up the crack so that when it is filled with new metal, the amount 
which is used will be sufficient, when the cylinder cools off, to fill the 
original space. Ordinarily, the walls of the crack should be held apart 
until the weld is completed, so that the width of the crack and the new 


PRE-HEATING 


23 


metal will contract together. If the crack runs from a point within 
the periphery all the way to the edge it may be opened up by heating 
at a point a little further in than the beginning of the crack. The 
welding is begun at the inner end of the crack, working toward the 
edge. 

The pre-heating should ordinarily be done rather slowly so as not 
to introduce sudden temperature changes and stresses. Slow heating 
is especially to be advised when there is a combination of thin and 
heavy parts. Similar remarks apply to the cooling, which should be 
slow to be safe; the cooling may be retarded by the use of asbestos 
sheeting or by packing the object in heated ashes or heated slaked 
lime. 

Temporary Furnace for Pre-heating 
When it is possible to pre-heat the entire casting, this seems to be 
the best way of taking care of expansions and contractions. Castings 



the size of which makes necessary special arrangements may be placed 
on a bed of fire-brick arranged with spaces between them. A tem¬ 
porary wall or furnace is then built around the whole, fire-brick being 
used for this also. These are arranged, of course, without the use of 
mortar, with very narrow openings between them, one method of con¬ 
structing such a wall being shown in Fig. 4. 

Flat steel bars may be employed just above the separated course of 
bricks A. The top course may be held in place by a steel band. The 
object of the open spaces is to provide a draft Charcoal is now filled 
in between the casting and the wall and the fire started. A sheet of 
asbestos is used as a cover. This cover should contain a number of 
holes so as to provide an exit for the gases. 

Hood used for Pre-heating Operations 

Another method is to make a hood of a material that is a poor con¬ 
ductor of heat. Such a hood is shown in vertical section in Fig. 5. 
The walls consist of two sheets of wire netting with an intervening 
space filled with asbestos. A hole, the wall of which is made of sheet 
iron, is provided at the top. Another aperture also lined with sheet 
iron is provided on one side of the vertical cylindrical wall. The bot¬ 
tom of the hood is furnished with an annular base ring of sheet iron. 













































24 NO. 125—AUTOGENOUS WELDING 

the netting and sheet iron being joined by welding. Provision should 
be made for lifting and lowering the hood, so that it can be let down 
over the casting which is to be pre-heated. To make a tight joint 
with the floor, some loose asbestos may be used as a foundation for 
the hood. A kerosene or other torch may now be inserted through 
the aperture in the side. Some kind of shield may be used just in¬ 
side of the side opening to divide the flame, so that, as far as possible, 
the casting will be encircled by it. Sometimes it is advisable to use 
auxiliary fires on shelves above the main fire at the bottom. This is 
especially to he recommended for tall castings, so that there will be 



no severe concentration of heat at one point. As already mentioned, 
the heating should be done slowly, the fires being started in a moder¬ 
ate way and gradually increasing in intensity. During the welding 
the hood must, of course, be raised, and when the welding is com¬ 
pleted the hood may again be lowered into position in order to retard 
the cooling. The oil torch should be brought into service again for a 
short period. It may then be shut off and the openings of the hood 
covered. In this way, slow and even cooling is assured. 

In general, after a welding operation, the casting should be reheated 
as soon as the welding is completed, and then covered with asbestos 
wool or scrap asbestos. The casting may also be buried in any of the 
materials ordinarily used for retarding the cooling of steel which is 
to be annealed. If the casting is of such a shape that it is not likely to 
crack, it may be cooled in the bed of charcoal in which it has been 
heated. 













PRE-HEATING 


25 


Pre-heating Temperatures 

Cast iron may be pre-heated to about 700 to 1000 degrees P. Gener¬ 
ally speaking, the higher the temperature of pre-heating, the less the 
danger of cracking when cooling. Aluminum castings should oe pre¬ 
heated to about 600 or 700 degrees F., the heat if possible being main¬ 
tained during the entire time of welding. To accomplish this, it is 
often advisable to cover the casting with asbestos and to leave only 
the working area exposed. Asbestos sheeting will be found satis¬ 
factory for keeping any class of work hot during the welding. 

Example of Repair Work by Oxy-acetylene Welding 

It may be of interest to refer to a specific case of welding performed 
by the Pullman Co. of Chicago. The bed of a hydraulic press was 
cracked; the casting weighed about 10 tons, and the crack was about 
10 inches long and 26 inches deep. The material of the bed was cast 
steel. The casting was placed on supports of brick about 14 inches 
high and a fire of wood and charcoal was maintained during the night, 
with the result that when the welding was begun the metal was at a 
red heat. A No. 10 Davis-Bournonville tip was used with a soft steel 
welding rod, two workmen carrying out the work. The time con¬ 
sumed for the welding operation was about five hours. The necessary 
enlargement of the crack was made by the oxy-acetylene flame. The 
expense was estimated at $19.16, and the result of the welding was 
very satisfactory. As the gas cost of the Pullman Co. is extraordin¬ 
arily low, for ordinary conditions the expense would, perhaps, be as 
follows: 


357 cubic feet of oxygen at 3 cents per cubic foot.$10.71 

143 cubic feet of acetylene at 1 cent per cubic foot. 1.43 

Labor . 7.40 

Fuel for pre-heating and annealing. 4.00 


$23.54 

The expense of replacing the casting by a new one would have been 
about $600. 







CHAPTER III 


OXY-ACETYLENE WELDING OP TANKS AND RETORTS 

One of the most important applications of the oxy-acetylene welding 
process is in connection with the manufacture of tanks and cylinders 
from sheet metal. In this field the new process promises to supersede 
soldering and riveting to a very large extent. The advantage over 
soldering consists principally in the increased strength of the joint 
and the ^quality of the expansion and contraction of the metal in the 
seam and in the work. There is also much less likelihood of the oc¬ 
currence of poisonous corrosions. 



Figs. 1 to 4. Illustrations showing Various Methods of Making 

Welded Joints 


In constructing vessels of sheet metal which are subjected to alterna¬ 
tions of high and low internal pressures, it is generally advisable to 
use special forms of joints at the corners or to avoid corner joints en¬ 
tirely. The stresses on the corner joints become very severe if the 
corners are of right-angled shape. If the corner is rounded, the ef¬ 
fect of the internal pressure at the joint is reduced. In Fig. 1, for 
example, if the welded joint is made at the square corner AB, it will 
be located at the point where the stresses on it, acting as indicated 
by the arrows, will be most severe. By forming the joint in the vari¬ 
ous ways shown in Fig. 2, the weld will be considerably strengthened 
as compared with a weld that merely joins the two sides at the corner 
AB in Fig. 1. It is still better, however, to remove the joint from the 
corner altogether. In Fig. 3 are shown the methods used for doing 
this. The best method of all to relieve .the welds of the excessive 
corner stresses is, of course, to change the horizontal section to that 
of a circle. 















































WELDING TANKS AND RETORTS 


27 


Tops and Bottoms of Sheet-metal Vessels 

One of the most difficult operations in the welding of tanks and 
retorts is the attaching of the tops and bottoms to cylindrical vessels. 
One of the first methods employed was that of making a joint as shown 
in Fig. 4. The welding was done from the outside and could be well 
finished. However, when the vessel was subjected to pressures from 
within, a combination of compressive and tensional stresses was pro¬ 
duced at the weld, thus causing cracks. To overcome this difficulty, 
joints as indicated in Fig. 5 were made. Where the metal is quite 
thin, sufficient contact of the surface can be secured by bending the 
metal outward to form a kind of a flange. By using more welding 
material than necessary to produce a joint flush with the adjoining 
surfaces, a stronger weld can also be made. 



Figs. 5 to 9. Methods of Welding Tops and Bottoms to Cylindrical Shells 


In all these cases, the top or bottom is assumed to be convex on the 
exterior. Another method, shown in Fig. 6, is to make it concave on 
the outside. Such forms are especially suitable for bottoms. In Fig. 
6 the rim of the bottom is bent and the edges of the bottom and of the 
cylinder are both beveled to provide a welding groove. Another 
method which does not necessarily include concaving is to bend up the 
rim of the bottom for a short distance, the dimensions of the piece 
being such that this rim snugly envelops the cylinder; the two may 
then be welded together. 

The use of flat tops and bottoms should, of course, be avoided. The 
expansion and contraction of these during welding are different from 
those of the cylinder. The flat piece does not yield to the cylinder, 
and, hence, the work is likely to be distorted. The convexing and 
concaving of the tops and bottoms provides a suitable margin for 
yield. Two forms of bottoms are shown in Fig. 7, in both of which 
elasticity in the diameter is provided for. The bending in of the edges 
onables the cylinder wall to support the bottom when the latter is 
under pressure from within. In some cases it may be necessary to 





















28 


NO. 125—AUTOGENOUS WELDING 


prevent diametral expansion of the cylinder when welding. A heavy 
removable band of metal in the form of a hoop may be used for this 
purpose. It is placed close up to the location of the seam. Most of the 
heat from the cylinder will then be absorbed and dissipated by this 
hoop. 

An interesting example of the application of the foregoing principles 
is afforded by a large containing vessel constructed by Munk & 
Schmitz, Cologne-Bayenthal, Germany. This vessel is a cylindrical 
shell, closed at top and bottom, and is formed of sheets 0.40 inch thick 
in the cylindrical portion and 0.83 inch thick in’the end portions. The 
vessel is 15 feet high and over 9 feet in diameter. Ail joints were 
made by the oxy-acetylene torch and the vessel successfully withstood, 
when tested, a pressure of 90 pounds per square inch. 

General Considerations in Welding- Tops and Bottoms to 

Cylindrical Vessels 

If the joining of the top to the cylindrical shell were made at the 
precise point where geometrically the side of the wall joins the top, 
as shown in Fig. 8, an outward pressure exerted from within and tend¬ 
ing to produce a spherical shaped bottom would tend to make the 
angles at A more obtuse and would thus produce a tensional stress on 
the inner portion and a compressive stress on the outer portion of the 
weld. Hence, it should be carefully noted that this method of joining 
ends to cylindrical shells is objectionable, and that the methods shown 
in Fig. 5 should, in general, be adopted. 

•It is also very important in forming welds of the type described not 
to forget the effects of expansion and contraction. It is recommended 
that the weld be hammered during the cooling-off process. The ham¬ 
mering should be discontinued while the metal is still quite hot, and 
should not be continued below the point where a horse-shoe magnet 
attracts the iron; in fact, at this point, one has perhaps gone a little 
too far. Subsequent to the cooling, the region that has been exposed 
to the high temperature should also be well annealed. This may be 
done by using two oil torches for gradual re-heating, one from the 
inside and one from the outside. Incidentally it might be mentioned 
that in performing the welding operation it is also often advisable to 
use two welding torches, in which case a weld of the double-V char¬ 
acter, as shown in Fig. 9, will be produced. The bottom of such a 
vessel should be so arranged that the weld is Tiot located where the 
weight of the’vessel itself comes upon it. 

As an interesting practical example, the illustrations Figs. 11, 12 
and A3 are> shown, indicating the progressive steps in welding a cylindri¬ 
cal shell, as well as the welding of a top and bottom to it. A diagram¬ 
matical view of a section of the welded container is shown in Fig. 10, 
the work being done by the Vilter Mfg. Co., Milwaukee, Wis. It will 
be seen that the top is convex and the bottom concave, as viewed from 
the outside. The shell is of %-inch boiler iron; the metal in the heads 
is Vz inch thick. The tank is 20 inches in diameter and 24 inches 
long. Both heads fit the inside of the shell as indicated. 


WELDING TANKS AND RETORTS 


29 


After welding, this tank was tested at a pressure of 1200 pounds 
per square inch. For carrying out the test, a hole was drilled on one 
side of the shell and a nipple inserted after tapping. The tank was 
then connected with a hydraulic press pump. At 1100 pounds pressure 
the nipple started to leak, but there was no leak at the welded joints. 
A No. 7 Davis-Bournonville tip was employed in making the straight 
W'eld in the shell, and a No. 8 tip was used for the ends. The straight 
W'eld was made in 45 minutes at a cost of $1.62 (exclusive of labor, 
but including depreciation); the circular weld at the convex end re¬ 
quired 2.67 hours and cost $6.99; the circular weld at the concave end 

required two hours and cost 
$5.24. At thirty cents per hour, 
the labor cost would be about 
$1.63, making a total cost of 
$15.48. These tanks are used at 
a maximum working pressure of 
three hundred pounds per square 
inch. A water cooled torch was 
employed in part of this work. 

Autogenous Welding of Copper 

While copper is normally 
tough and ductile, it enters a 
brittle stage when heated to 
about 1650 degrees F. This 
brittleness continues up to the 
melting point (at about 1930 
degrees F.) In order to weld 
copper it must be heated to this 
critical stage. At these high 
temperatures copper possesses a 
remarkable capacity for absorb¬ 
ing certain gases. If exposed to 
the atmosphere while at a white heat it absorbs oxygen. 

Another quality of copper is that when heated to a high tem¬ 
perature, quenching in water has a softening or annealing effect. 
Copper that has been highly heated and oxidized will, however, begin 
to fracture when one commences to hammer it, even if it has been 
annealed; hence, it is very important to prevent oxidation when weld¬ 
ing, and by proper management of the outer flame of the oxy-acetylene 
torch the operator may succeed in preserving the new copper in the 
weld from oxidation. To make perfect work, however, it is necessary 
also to preserve the old copper, and here is where difficulties are met 
with. On account of the great heat conductivity of copper, a high tem¬ 
perature will be found for some distance on either side of the joint to 
be welded. Unless the operator can protect this outlying region, the 
results will not be satisfactory. 

It is well known that phosphorus has a great avidity for oxygen. 
If, then, instead of a very pure copper we use a phosphor-copper alloy 



Pig-. 10. Example of Tank welded by the 
Oxy-acetylene Process 












30 


NO. 125—AUTOGENOUS WELDING 



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Boracic acid may be used instead of borax. The powder Chapter I, where some additional information on this sub- 
is prepared by mixing the boracic acid and the phosphor- ject is given. It is also well to consult the catalogues of 
natrium. Welding powders of this description form a film firms making autogenous welding outfits. 









WELDING TANKS AND RETORTS 31 

The Welding” of Aluminum 

The coefficient of expansion of aluminum is equal to twice that of 
steel and its melting point compared with that of copper and steel is 
rather low, being about 1215 degrees F. It is also comparatively weak 
in tension. Cast aluminum resists a tensional stress of about 10,000 
pounds per square inch. Because of this weakness, and on account of 
its high rate of expansion and contraction, it is a difficult material to 
weld. As its heat conductivity is high, it is also difficult to localize the 
region of the high temperature. Oxidation of aluminum, however, can 
be avoided by the use of a proper flux. 

While the total expansion and contraction from 100 degrees F. to 
the fusion point or welding temperature is about the same for cast 
iron and aluminum, because of the fact that the fusion point of cast 
iron is at a temperature about twice that of the fusion point of 
aluminum, the expansion and contraction, due to temperature changes, 
take place much more rapidly with aluminum, and the operator must 
use special care on this account. The low temperatures dealt with 
when welding aluminum make the pre-heating easier, but the operator 
must guard against not exceeding the fusion temperature. It is some¬ 
times possible to make slight saw cuts here and there, and thus assist 
in making the effects of expansion and contraction harmless. These 
cuts, of course, must be repaired when the main operation is com¬ 
pleted. Aluminum should never be welded without a flux. If welding 
is attempted without a flux, little globules consisting of aluminum 
within and a coating of alumina (oxide of aluminum) will appear. 
In order to eliminate these by heat, it would be necessary to raise the 
temperature to the melting point of the oxide of aluminum, which is 
about 5400 degrees F. A flux consisting of the following ingredients 
has been recommended: chloride of sodium, 30 parts; chloride of 
potassium, 45 parts; chloride of lithium, 15 parts; fluoride of potas¬ 
sium, 7 parts; and bisulphate of sodium, 3 parts. 

When melting new metal from a rod, it is good practice to keep the 
rod constantly submerged in the molten bath of the metal in the weld¬ 
ing groove, which for aluminum should be much larger than usual. If 
no powder is used, the oxidation is then confined to the upper sur¬ 
face. The main point to remember when welding aluminum is that the 
fusion point of this metal is very low; hence, the working flame 
should be kept further away from the metal than is usually the case 
when welding cast iron and steel. The torch should be so adjusted as 
to furnish an excess of acetylene. There need be but little fear of 
carbonizing the metal, for the reason that the temperature of the work 
is comparatively low. 

The Welding” of Household Utensils 

Some forms of household utensils, such as, for example, coffee and 
tea pots, cause considerable difficulties in their manufacture, particu¬ 
larly in connection with the attachment of the spout. Soldering has 
been used to a great extent in making these joints. However, the 


32 


NO. 125—AUTOGENOUS WELDING 


basic material of the solder is altogether different from the material 
Ignited. The uses to which the vessels are put expose the joints to the 
action of acids, and galvanic currents are set up which injure the joint. 
Aluminum vessels are especially exposed to the action of these cur¬ 
rents, because this metal is electro-positive to nearly all of the com¬ 
mon metals. One means to obviate the difficulty is to bend the metal 
of the main vessel or body inwards at the hole for the spout. The 
material of both body and spout is then bent into a fold on the in¬ 
terior, no soldering material being used. The presence of this fold 
on the inside, however, is very objectionable. Even though it is closed 
when the vessel is new, the effect of repeated heatings is liable to 
open it, and the crevice becomes a trap for various small particles. 



Figs. 14, 15 and 16. Methods of Welding Spouts to Household Utensils 


which prevents effective cleaning. The oxy-acetylene welding presents 
the best solution of the foregoing difficulties. 

When seeking to unite the spout and body by the oxy-acetylene torch, 
the worker is, however, confronted with several difficulties, especially 
if the sheet metal be aluminum. The expansion and contraction of 
aluminum, due to temperature changes, as already mentioned, is very 
rapid, so that the operator must guard against distortions of the work. 
The melting point of the metal is low, so that holes are apt to be made 
in thin metal. Heated aluminum is very readily oxidized with the 
result that a proper intermingling of the material is difficult. In view 
of these facts, it is recommended that the joint be placed away from 
the main body, that welding wire be dispensed with, and that a suit¬ 
able flux be employed. In Pig. 14 is shown a joint which eliminates 
the necessity for the welding wire; the spout fits closely into the hole 
and is introduced far enough to protrude about % inch into the in¬ 
terior, the projection thus furnishing the welding material. There is 
considerable advantage, of course, in thus eliminating the handling of 
the wire as far as the worker is concerned, and another advantage is 
that the welding material is precisely the same as the material of the 








WELDING TANKS AND RETORTS 


33 


work. It is difficult, however, to operate on the interior, but this 
difficulty may be reduced by using a tip of special form. The appear¬ 
ance of the exterior, however, is good. 

Another form of joint is shown in Fig. 15. Here the diameter of the 
hole is first made smaller than the interior diameter of the lower end 
of the spout. The material is then bent outwards to form a ridge of 



Fig. 17. Example of Welding Copper. Kettle is 5 feet 6 inches in 
Diameter, 31 inches deep and used under Pressure. All 
seams are welded on Both Sides 


the same diameter as that of the spout end. The body and spout can 
then be butt-welded by using welding wire. It is preferable, how¬ 
ever, to bend the edge of the projection from the vessel outward, thus 
supplying the needed welding metal, or the auxiliary metal may be 
provided by bending the edge of the spout outwards, a joint of this 
kind being shown in Fig. 16. In either case, the ring of metal pro¬ 
truding at the joint will not be thicker than % inch in a radial direc¬ 
tion. In both cases, the interior is smooth. 










CHAPTER IV 


AUTOGENOUS WELDING AS A MEANS OP 
REPAIRING CYLINDERS 

Breakages in automobile cylinders can be divided into three main 
classes which cover at least ninety per cent of the cases. The ma¬ 
jority of these breakages can be satisfactorily repaired by means of the 
oxy-acetylene flame, the cylinder being as good as new. Additional 
metal is added where necessary from a rod of the same material, and 
the process consists in practically recasting the part locally. 

Autogenous welding is proving a great boon to those who are unfor¬ 
tunate enough to have their automobile cylinders broken, as they can 
be satisfactorily welded and in the majority of cases, with a little trim¬ 
ming off, the repairs will not show. Cylinders with cracks are some¬ 
times brazed, but owing to the necessity of heating the whole cylinder 
to a good red heat to even up the contraction strains, so as not to 
crack when cooling, the bore of the cylinder is generally warped, and 
the job requires a lot of flnishing as the spelter and flux spread con¬ 
siderably and are difflcult to remove. Also, owing to the dirt and rust 
in the crack it is difficult to get the brazing below the surface; the 
high temperature necessary will sometimes crack the cylinder else¬ 
where. 

Water Jackets Broken by Freezing: 

The largest class of cylinder breakages—mainly due to carelessness 
or misfortune, probably in most cases the former—is caused by al¬ 
lowing the water jacket to freeze, resulting in the breaking of the 
water jacket wall. Also, it has frequently happened that when ship¬ 
ping a car by rail in winter the drain cocks were opened, but due to 
some pocket in the water system (in some cases very small ones) 
which did not drain, the cylinders have become flt subjects for the 
autogenous welder. 

Curiously enough the majority of cylinders cast from the same 
patterns will break in just the same place when frozen. In a number 
of cases the break causes a piece of the wall of the water jacket to 
be entirely detached, and the breaks occur so nearly alike, in similar 
cylinders, that it would be possible to take the detached piece from 
one and weld it into another, even the smaller irregularities coinciding. 

When a break of this nature is autogenously welded, by means of 
the oxy-acetylene flame, the crack or edge of the broken part is pre¬ 
pared so as to leave a groove nearly through the metal. The whole 
part is then uniformly heated to about ffve hundred degrees F. This 
temperature is not high enough to warp the bore, as has been re¬ 
peatedly proved by careful measurements before and after treatment. 
The sides of the groove are fused together and filled from a rod of 


REPAIRING CYLINDERS 


35 


cast iron. The resulting weld is very neat in appearance; it gener¬ 
ally requires no finishing and is as strong as the original wall. As a 
very small number of heat units are absorbed by the part, owing to 
the intense heat of the fiame fusing the metal before the heat has 
time to spread, there is seldom any trouble with cracks when the metal 
contracts in cooling. The cylinders A and B, Pig. 1, show common 
types of breakages which are being satisfactorily welded every day. 
The crack in A is seventeen inches in length. Both cylinders are 
grooved out ready for welding. 



Fig:. 1. Two Cylinders with Cracked Water Jackets prepared for 
Welding. Twin Cylinders with Broken Flanges to be Welded 

Cylinder Wall Broken 

The next class of breakages, in order of frequency of occurrence, is 
that in which the wall of the cylinder, combustion or valve chamber, is 
broken or cracked. These breaks are, in most cases, due to freezing, 
but a certain number of them are due to the designer making a large 
fiat surface without adequate ribbing to support the pressure of the 
explosion. * 

Another cause is the breakage of the connecting-rod, allowing the 
piston to strike the top of the cylinder. Serious damage from this 
cause occurs most frequently in two-cycle engines as the deflector on 
the piston readily punches a hole in the combustion chamber wall. 

This class of breakages is the most difficult to repair, as it is neces¬ 
sary in most cases to cut out a section of the water jacket to be able 
to work on the inner wall, the only exception occurring when the 
break happens to be opposite a large hand hole. This operation has a 









36 


NO. 125—AUTOGENOUS WELDING 


singular resemblance to the well-known trepanning operation per¬ 
formed upon the human skull. 

It can be readily seen that it is practically impossible to make a 
repair when the break occurs between two cylinders or behind the 
valve chamber, as these parts cannot be reached with the small flame. 
If the crack occurs in the bore, it is necessary to carefully weld to 
within a sixteenth inch of the bore, or the finished surface will be 
spoiled; the crack left in this way is of small importance, as suf¬ 
ficient metal can be built on the outside so that there is no doubt about 
the strength. After welding the break, the section of the water jacket 
which was removed is welded back in place. 



Fig. 2. Cylinder A repaired by inserting a Steel Piece, bent to Shape, 
and autogenously welded in Place. Cylinder B has had Flange repaired 


As it often is impossible to determine the length or exact locality 
of the cracks before cutting away the jacket and as it is desirable to 
remove as small a section as possible, it often is found necessary to 
cut additional pieces out, thus necessitating welding a number of small 
pieces back in place when finishing the job. To restore these pieces 
sometimes is impracticable, and a sheet steel substitute must be ham¬ 
mered out and welded in place. With care this piece can be shaped 
so as to coincide with the piece removed, and cannot be detected when 
welded in place. The part cut away was thus neatly replaced by sheet 
steel, as shown at A, Fig. 2. 

The water in freezing will often crack both the water jacket and 
cylinder wall. The former being readily seen is generally thought to 
be the full extent of the damage, particularly as it is practically im¬ 
possible to make a test until the crack is repaired. The work may 
then have to be cut out to find further defects. 

The cover plate on the cylinder shown in Pig. 2 was also broken in 





REPAIRING CYLINDERS 87 

freezing, at the same time as the cylinder wall was broken, and is 
shown welded. 

Fig. 3 shows a cylinder having a crack eight inches long, located 
at the corner of the combustion head, that was welded. The part cut 
out of the water jacket is also shown. It will be noticed that this 
operation required cutting through a supporting lug. 

Broken Flang-es 

The next order of breakages in point of number are those in which 
all, or a portion of the flange, which holds the cylinder to the crank 
case is broken away, due either to insufficient metal to withstand the 
strain or to carelessness in assembling. 



f-f 

Fig. 3. Cylinder Cracked in Inner Fig, 4. Air-cooled Cylinder on 
Wall, showing Large Section which Boss for Ignition 

of Outer Wall removed Plug was autogen- 

to weld the Crack ously welded 

These breakages occur in two ways; the wall of the cylinder may be 
broken away or part of the flange may be cracked off. In the latter 
case it is an easy matter to make the repair, but when the break runs 
through into the bore of the cylinder considerable care is required. 
First it is necessary to consider whether it is desirable to weld in 
the bore W'hich would then require machining or at any rate filing out, 
or only groove and weld from the outside to within a sixteenth inch 
of the bore, sufficient metal being added to the outside to insure 
strength. The latter method, of course, leaves the crack on the inside,- 
wdiich can, however, be smoothed down and is not objectionable for a 
repair job, as it does not interfere with the satisfactory operation of 
the motor in any way. 

In addition to these three classes, there is a large variety of other 
breakages, no two of which are alike, that can be repaired success¬ 
fully by the oxy-acetylene torch. Considerable welding can also be 
carried out by the manufacturer, such as the welding on of additional 
bosses for dual ignition systems, as shown in Fig. 4, building up bosses 
that did not “fill” in castings, etc. 











CHAPTER V 



MANUFACTURE OP TUBING BY AUTOGENOUS 

WELDING 

The trend of industrial processes, today, is in the direction of 
continuity. If a process can be made continuous, a great advantage 
is gained, other things being equal. It is no wonder, then, that in 
consequence of the enormous demand for water, gas and steam 
piping, very determined efforts have been made to produce tubing by 
the process of rolling. The efforts have been successful, and steel 


Fig, 1. Tube Rolling Machine built by August Schmitz, Dusseldorf, Germany 

tubing is now made in large quantities by this method. Strips of 
flat steel are rolled longitudinally between successive pairs of rolls 
until the edges meet or overlap. They are then butt- or lap-welded. 

In Germany, tubing is being made by the rolling of sheet metal 
and the subsequent welding with oxygen and acetylene, the process 
being continuous, and a special welding machine being used. The 
rolling machine is of the type shown in Fig. 1. This machine receives 
the metal in long flat strips, which have either been specially rolled 
or cut to the required width. The first operation is accomplished by 
a pair of rolls which bend the longitudinal edges upward. These bent- 
up edges will ultimately form the “roof” of the tube. It is important 












MANUFACTURE OF TUBING 


39 


that the degree of curvature of the bends shall be precisely that of the 
finished tube. Another pair of rolls just ahead receives the strip and 
bends it into a U-shaped form; the upper ends of the U-curve, how¬ 
ever, are bent toward each other because of the side bends formed by 
the previous pair of rolls. Another pair of rolls is now employed to 
receive the U-shaped strip and cause it to approximate still more closely 
the tube-shape. Finally, another pair of rolls complete the bending 
to shape; a mandrel is employed with this pair. In case very elastic 
material is employed, it is advisable in the first pass to bend the 
axial portion so that when the tube is shaped it will point in toward 
the inside of the tube. In the last operation, this bend will be elimin¬ 
ated by the mandrel. The object is to obtain a joint with no tendency 
to open. 

When a strip which has been cut from a sheet in the ordinary way is 
thus bent together, there will be a V-shaped groove along the joint. 



Fig. 2. Principle of Autogenous Tube-welding Machine 


The reason for this is that the external circumference of an annular 
ring is longer than the internal one. The strip is of the same width 
on both sides, so that when one side is bent to form a complete inner 
circle there is not enough material for the outer circle. The weld 
can still be made, but as machine welds use no additional metal, the 
section at the weld will be thinner than it ought to be. If the tubing 
is made of quite thin metal, no especial difficulty will arise from the 
formation of a groove; but when the wall is rather thick, strips which 
have been especially rolled to provide a greater width on one side 
than on the other should be used. When such a strip is bent to the 
final shape, we have a narrow V-shaped groove with ridges on each 
side. A narrow groove is advisable, because it admits the flame to 
the entire depth of the joint. 

The welding machine is rather simple. Two pairs of compression 
rolls are placed a short distance apart, as indicated in the diagram¬ 
matical view. Fig. 2. These rolls carry the tube along, the one pair 
receiving it from the tube rolling mill. Between the two pairs of rolls 
a standard is placed to which is secured the device which holds the 








40 


NO. 125—AUTOGENOUS WELDING 


torch. This latter has its tip directed downward and toward the un¬ 
welded joint. The angle of inclination is about 45 degrees. The tub¬ 
ing, as it is fed along by the first pair of rolls, can scarcely be depended 
upon to keep its unwelded joint in a constantly uniform position. It 
is, however, necessary that the working flame of the torch and this 
joint shall be in an exact relation to each other. Therefore, a holder 
is provided which carries a roll or wheel having a thin edge or pro¬ 
jection on its periphery. This edge enters into the groove at the 
joint and controls its position just before it reaches the torch. This 
machine is made of the duplex type, so that two welding opera¬ 
tions may be handled at the same time; a torch and the necessary 
rolls are arranged on each side of the bed. Comparatively thin tub¬ 
ing, say 0.04 inch in thickness, can be welded at the rate of about 8 
inches per second, or about 40 feet per minute. 

It is frequently the custom in the bicycle industry to draw tubing 
to an oval or elliptical section. The most severe stresses to which 
such elliptical tubing is subjected would tend to injure the weld if the 
latter should be located at the end of either axis of the ellipse. It 
has been found advisable, therefore, to locate the seam to one side of 
the “sharp” end of the ellipse. A Swedish charcoal iron, containing 
very little carbon, is said to be most suitable for this class of work. 

In the rolling of tubes of small diameter, it is permissible to roll 
in a longitudinal direction, but when we come to greater diameters, 
it becomes necessary, or at least advisable, to discard the continuous 
method and use rolls or other devices whose axes are parallel with 
that of the tube. Machines specially built for this service bend the 
sheets quickly to the required cylindrical form. Diameters of 3 to 10 
inches are readily handled, the material having a thickness up to 
inch. The forming process requires from 7 to 12 minutes for each sec¬ 
tion of tubing, according to the length. Large tubes are usually 
welded autogenously by hand. 

That large pipe made by the oxy-acetylene process is reliable is in¬ 
dicated by the following test: Two sections of such pipe, each about 
39 feet long and 35 inches inside diameter had their flanges bolted to¬ 
gether to form a single length of nearly 80 feet. The supports were 
placed at the ends so that the full length between them was unsup¬ 
ported. Then the double length of tubing was loaded with about 
thirty men, or, in other words, a load of more than two tons was 
supported. Of course this test does not take into account the question 
of the “water-tightness” of the weld. However, a test was carried out 
upon another piece of welded tubing—this time a bend—of about 2 
feet inside diameter. The tube did not leak under a pressure of about 
365 pounds per square inch. Another piece of tubing about 31 or 32 
inches in diameter has been made by the welding process from ma¬ 
terial which was about 0.4 inch thick. A drainage system for a lock 
of the Kaiser-Wilhelm canal contains about 2000 feet of pipe welded 
by the autogenous process. One German firm is manufacturing hot 
water heaters by the same process. 



No. 67. 
No. 68. 
No. 69. 
No. 70. 
No. 71. 
No. 72. 


Boilers. 

Boiler Furnaces and Chimneys. 

Feed Water Appliances, 

Steam Engines. 

Steam Turbines. 

Pumps, Condensers, Steam and Water 
Piping. 


LOCOMOTIVE DESIGN AND BAILWAY SHOP 
PRACTICE 

No. 27. Locomotive Design, Part I. 

No. 28. Locomotive Design, Part II. 

No. 29. Locomotive Design, Part III. 

No. 30. Locomotive Design, Part IV. 

No. 79. Locomotive Building. — Main and Side 
Bods. 

No. 80. Locomotive Building.—Wheels; Axles; 
Driving Boxes. 

No. 81, Locomotive Building. — Cylinders and 
Frames, 

No. 82. Locomotive Building.—^Valve Motion. 

No. 83. Locomotive Building.—Boiler Shop Prac¬ 
tice. 

No. 84. Locomotive Building.—Erecting. 

No. 90. Railway Repair Shop Practice. 


ELECTRICITY—DYNAMOS AND MOTORS 

No. 34. Care and Repair of Dynamos and Motors. 
No, 73. Principles and Applications of Electricity, 
—Static Electricity; Electrical Measure- 
ments; Batteries. 

No. 74. Principles and Applications of Electricity. 

—Magnetism; Electric-Magnetism; Elec¬ 
tro-Plating. 

No. 76. Principles and Applications of Electricity, 
—Dynamos; Motors; Electric Railways. 
No. 76. Principles and Applications of Electricity. 

—Telegraph and Telephone. 

No. 77, Principles and Applications of Electricity. 
—Electric Lighting. 

No. 78. Principles and Applications of Electricity. 
—Transmission of Power. 

No 115. Electric Motor Drive for Machine Tools. 


HEATING AND VENTILATION 

No. 39. Fans, Ventilation and Heating. 

No. 66. Heating and Ventilation of Shops and 
Offices. 

IRON AND STEEL 
No. 36. Iron and Steel. 

No. 62. Hardness and Durability Testing of 
Metals. 

No. 117. High-speed and Carbon Tool Steel. 

No. 118. Alloy Steels. 

FORGING 

No. 44. Machine Blacksmithiiig. 

No. 45. Drop Forging. 

No. 61. Blacksmith Shop Practice. 

No. 113. Bolt, Nut and Rivet Forging. 

No. 114. Machine Forging, 

No. 119, Cold Heading. 

MECHANICAL DRAWING AND DRAFTING- 
ROOM PRACTICE 


No. 2. 
No. 8. 

No. 33. 

No. 85. 

No. 86. 
No. 87. 
No. 88. 


No. 108. 
No. 109. 


No. 35. 
No. 110. 


Drafting-Room Practice. 

Working Drawings and Drafting-Room 
Kinks. 

Systems and Practice of the Drafting- 
Room. 

Mechanical Drawing.—Geometrical Prob¬ 
lems. 

Mechanical Drawing.-Projection. 
Mechanical Drawing.—Machine Details, 
Mechanical Drawing.—Machine Details. 

DIE-CASTING 

Die-Casting Machines. 

Die-Casting, Dies and Methods. 

MISCELLANEOUS 

Tables and Formulas for Shop and Draft¬ 
ing-Room. 

Extrusion of Metals. 


MACHINERY’S DATA BOOKS 

Machinery’s Data Books include the material in the well-known series of Data 
Sheets published by Machinery during the past fifteen years. Of these Data Sheets, 
nearly 700 were published and 7,000,000 copies sold. Revised and greatly amplified, 
they are now presented in hook form, kindred subjects grouped together. The price 
of each book is 25 cents (one shilling) delivered anywhere in the world. 


No. 1. 

No. 2. 
No. 3. 

No. 4. 

No. 5. 
No. 6. 
No. 7. 
No. 8. 

No. 9. 
No. 10. 


LIST OF MACHINERY’S DATA BOOKS 


Screw Threads. 

Screws, Bolts and Nuts. 

Taps and Dies. 

Reamers, Sockets, Drills and Milling Cut¬ 
ters. 

Spur Gearing, 

Bevel, Spiral and Worm Gearing. 
Shafting, Keys and Keyways. 

Bearings, Couplings, Clutches, Crane 
Chain and Hooks. 

Springs, Slides and Machine Details. 
Motor Drive, Speeds and Feeds, Change 
Gearing, and Boring Bars. 


No. 11. 

No. 12. 
No. 13. 
No. 14. 
No. 15. 
No. 16. 
No. 17. 
No. 18. 
No. 19. 
No. 20. 


Milling Machine Indexing, Clamping De¬ 
vices and Planer Jacks. 

Pipe and Pipe Fittings. 

Boilers and Chimneys. 

Locomotive and Railway Data, 

Steam and Gas Engines. 

Mathematical Tables. 

Mechanics and Strength of Materials. 

Beam Formulas and Structural Design, 

Belt, Rope and Chain Drives. 

Wiring Diagrams, Heating and Ventila¬ 
tion and Miscellaneous Tables. 

, f- 



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couplings—Friction brakes—Cams, cam design and cam milling—Spur gearing—Bevel 
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